The present disclosure relates to a touch panel and a method for manufacturing the same.
As computers using digital technologies are developing, computer-assisted devices are being developed. Personal computers, portable transmission devices, and other personalized information processing devices perform text and graphic processing using various input devices such as a keyboard, a mouse, and the like.
However, as an information-oriented society rapidly advances, the scope and use of computers are expanding. Thus, it may be difficult to efficiently drive new product development by using only the keyboard and mouse as input devices. Thus, a need for devices having a simple structure, low malfunction rate, and an easy-to-input information function is increasing.
Technologies for input devices are improving reliability and durability, and focus on innovation, design, processing-related technologies, and the like, beyond general functionality. For this, touch panels have been developed as input devices that are capable of inputting information such as text, graphics, menu selection, and the like.
Such a touch panel may be installed on a display surface of a flat panel display device such as an electronic organizer, a liquid crystal display device (LCD), a plasma display panel (PDP), an electroluminescence (E1) device, and the like, and an image display device such as a cathode ray tube (CRT), to allow an user to select desired information while seeing the image display device. The touch panels may be classified into a resistive type touch panel, a capacitive type touch panel, an electro-magnetic type touch panel, a surface acoustic wave (SAW) type touch panel, and an infrared type touch panel. The various types of touch panels are adopted for electronics, taking into consideration limitations on signal amplification, resolution differences, difficulty of design and processing, optical quality and/or characteristics, electrical quality and/or characteristics, mechanical quality and/or characteristics, environmental concerns, input characteristics, durability, and economic feasibility. These days, the resistive type and capacitive type touch panels are being widely used in various fields.
The capacitive touch panel includes an add-on type touch panel and a cover glass-integrated or display-integrated touch panel using a lamination structure. The add-on type touch panel includes GFF, GF2, GG, and the like, and the cover glass-integrated touch panel includes G1F, G2, and the like.
GFF may be the most common touch panel having a structure in which two PET films or two parts of a PET film on which Rx (e.g., signal reception) patterns for detecting an X-axis coordinate value are laminated in the form of a thin film, and a PET film on which Tx (e.g., signal transmission) patterns for detecting a Y-axis coordinate value are laminated in the form of a thin film, are laminated or layered on a bottom surface of a cover glass.
The GF2 has a structure in which the Rx and Tx patterns are respectively deposited in the form of a thin film on top and bottom surfaces of the PET film, and then, the PET film is laminated or layered on the bottom surface of the cover glass. The GG has a structure in which the Rx and Tx patterns are respectively deposited in the form of a thin film on top and bottom surfaces of a transparent substrate formed of glass instead of an ITO film, and then the transparent substrate is laminated or layered the bottom surface of the cover glass.
The add-on type GFF is the most common type touch panel. However, in recent years, demands for mobile phones having a large screen and a small size are increasing with an increase of utilization of the mobile phones. Thus, a development process with respect to the cover glass-integrated and display-integrated touch panels has become an issue.
Generally, when the screen increases, the pattern layer(s) in the active region of the touch panel increase, and thus, a bezel that corresponds to the non-active region of the touch panel or touch screen may also increase in width. As a result, the development process for realizing slim electronic devices having a large screen may be limited.
FIG. 1 is a schematic plan view of a touch panel according to a related art, and FIG. 2 is a plan view illustrating Tx and Rx pattern layers in FIG. 1.
Referring to FIGS. 1 and 2, a touch screen panel 100 according to the related art includes a transparent substrate 101 formed of a general film or glass, a Tx pattern layer 130 deposited in the form of a thin film on a top surface of the transparent substrate 101, and a Rx pattern layer 120 deposited in the form of a thin film on a top surface of the Tx pattern layer 130. The Tx pattern layer 130 includes a plurality of Tx electrodes 107 detecting a Y-axis coordinate value and a Tx metal interconnection 103 connected to an end of each Tx electrode 107 to transmit an electrical signal to a flexible printed circuit board (FPCB) 300. The Rx pattern layer 120 includes a plurality of Rx electrodes 122 detecting an X-axis coordinate value and an Rx metal interconnection 110 connected to an end of each Rx electrode 122 to transmit an electrical signal to the FPCB 300.
The plurality of Rx and Tx electrodes 122 and 107 are disposed on the transparent substrate 101 in a lattice shape to form an active region, and the metal interconnections 110 and 103 are disposed to one side of the electrodes 122 and 107 to respectively correspond to the electrodes 122 and 107 and form a bezel region.
As shown in FIGS. 1 and 2, the Tx metal interconnection 103 in the bezel region may correspond to the Tx electrode 107 to transmit the electrical signal of the Tx electrode 107 to the FPCB 300. Therefore, according to properties in the panel structure, the more Tx electrodes 107 that are present, the more Tx metal interconnections 103 there are, increasing the width of the bezel on each of the left and right sides of the transparent substrate 101 on which the Tx electrodes 107 is laminated.
In devices such as smart phones including a touch screen, a display or a region touchable by a user may be maximally utilized by reducing the bezel region. However, reduction of a trace line region such as the metal interconnection reaches its limit due to limitations in the processing technologies. Also, when the trace lines are on both left and right sides of the touch panel, panel characteristics may be non-uniform due to differences in the delay of a driving signal, depending on the direction of the trace line.